Coil winding machine



Oct. 18, 1955 H. c. PASINI COIL WINDING MACHINE Filed May 3, 1951 CONSTANT SPEED MO OR SPEED CONTROL KFELE SEZEmXQS 255T? V 9 Aera/a 67 P557222 BY 7 United States Patent Ofitice 2,721,638 Patented Oct. 18, 1955 con. WINDING MACHINE Harold C. Pasini, Westwood, N. .L, assignor to George Rattray & Co. Inc., Jamaica, N. Y., a corporation of New York Application May 3, 1951, Serial No. 224,363

3 Claims. (Cl. 242-9) The present invention relates to methods and machines for producing helical windings in which the spacing between adjacent turns is non-uniform and is controlled in accordance with a predetermined desired arrangement.

In the production of variable resistors which comprise a movable contact engaging a fixed resistance element, it is frequently desirable to provide an arrangement in which successive uniform mechanical displacements of the movable contact will result in non-uniform increments in the value of the variable resistance. The resulting curve of resistance plotted against displacement of the movable contact is arranged to follow a curve having a specific shape, such as a logarithmic or parabolic curve. Curves of other shapes may also be desirable, the particular shape in each instance depending upon the specific electrical circuit in which the variable resistor is to be used.

It is among the objects of the invention to provide a method and a machine for producing helical windings of non-uniform spacing, the spacing being accurately controlled from point to point throughout the length of the winding in accordance with a predetermined pattern.

A further object of the invention is to provide a machine of this character in which the predetermined spacing pattern may be conveniently altered at will.

Another object of the invention is to provide a winding machine in which the spacing between adjacent turns may be varied in successive steps, it being so arranged that as great a number of steps may be utilized as may be required in order to achieve conformity to a particular displacement resistance curve within specified limits of accuracy.

Still another object of the invention is the provision of winding machine of this character which is suitable for use with wires, threads, or other filamentary materials regardless of whether or not they are electrically conductive.

Other and further objects will become apparent upon reading the following specification together with the accompanying drawing forming a part hereof.

Referring to the drawing:

Figure l is a diagrammatic representation of a winding machine embodying the invention.

Figure 2 is a graph showing an ideal resistance curve and the resistance curve of a resistor wound in accordance with the invention.

Referring to Figure 1, there is shown an insulating strip or other windin supporting means 11 partially wound with resistance wire. Strip 11 is supported at one end by a rotatable head stock 12 and at the opposite end by a rotatable tail stock 13. Both head stock 12 and tail stock 13 are driven together at identical speeds by gears 14 and 15 respectively, which mesh with gears 16 and 17 carried by a common shaft 13 which are in turn driven through suitable reduction gearing 19 by constant speed driving means shown by way of illustration as a constant speed electric motor 20. Motor 20 may be a synchronous motor or it may be of any other desired type which will provide the required constancy and stability of speed.

Extending parallel to shaft 18 is a lead screw 21 which carries a nut 22. Nut 22 is free to travel along the lead screw 21 as the screw 21 rotates, rotation of nut 22 being prevented by suitable guide means shown as the shaft 18 which extends parallel to screw 21. A wire guiding member 23 carried by nut 22 feeds a resistance wire 24 to the rotating insulating strip 11. A wire, thread, or other filament 24 is fed from a source of supply including suitable tension regulating means (not shown).

One end of lead screw 21 is journaled at 25 in a supporting member 26, the opposite end being driven through suitable reduction gearing designated generally as 27 by variable speed driving means shown illustratively as a variable speed electric motor 23.

The speed of variable speed motor 28 is regulated and controlled by a speed control 29. Speed control 29 may be of any conventional and well know type which governs the speed of motor 28 in accordance with the magnitude of an electrical voltage applied thereto via conductors 30 and 31. For example, motor 28 may be a direct current motor whose field current is regulated by speed control 29 in accordance with the magnitude of the control voltage between conductors 30 and 31. Devices of this character are well known in the art, and any appropriate type may be selected for use in a particular winding machine.

In certain instances, it may be desirable for the variable speed driving means comprising the units 23 and 29 to consist of variable speed gearing or other mechanical arrangements wherein the speed ratio may be varied and controlled by the magnitude of the control voltage between conductors 30 and 31. In the case of the latter arrangement, a single constant speed motor may drive the insulating strip 11 through fixed ratio gearing and the lead screw 21 through variable ratio gearing.

The respective positions of the variable speed and constant speed drives may be interchanged, if desired. In the event that they should be so interchanged, the insulating strip 11 will be rotated at a speed which will vary in accordance with the magnitude of the control potential between conductors 30 and 31, the lead screw 21 being driven at constant speed.

The magnitude of the control potential between condoctors 30 and 31 varies in accordance with longitudinal position of wire guiding member 23 along the rotating insulating strip 11, and thus controls the pitch of the winding in accordance with the control potential. The pitch of the winding may be varied as desired by varying the control potential.

In order to vary the control potential in accordance with a desired predetermined pattern, there is shown by Way of illustration, a commutator 32 comprising a plurality of commutator segments 33 which are selectively engaged by a moving contact or brush 34. Brush 34 is supported by an insulating member 35 which is carried by nut 22, and accordingly, the position of brush 34 varies with respect to the several commutator segments 33 directly in accordance with the travel of nut 22 along lead screw 21, and hence in accordance with the position of wire guiding member 23 along the revolving insulating strip 11 which is being wound with resistance wire.

Each of the commutator segments 33 is connected through a resistor 36 to a suitable source of direct current potential shown diagrammatically as a battery 37. One side of the control potential source is connected to conductor 31 which extends to the speed control 29. The control potential circuit is completed from speed control 29 via conductor 30 and flexible conductor 38 to the movable brush 34 and the particular commutator segment 33 with which brush 34 may then be in engagement.

For simplicity of illustration, commutator 32 has been j betweenthe points and C along the curve.

shown as rectilinear in construction. If desired, it may be made circular in shape and the brush 34 may bedriven together-with lead screw 21, or moved simultaneously and together with nut 22.

' Irrespective of the particular 'means employed for varying the control potential applied to the speed control 29, the control potential will vary in'accordance with the longitudinal position of wire guiding member 23 along the insulating strip 11, thereby controlling the pitch of the winding at each point along the strip 11 which is being wound with resistance wire.

In the case of a commutator, such as the commutator 32 shown in Figure 1, the brush 34 will momentarily bridge two adjacent commutator segments. The'individual resistors 36 connected in series with each segment 33' prevent a short circuit during this extremely short interval of bridging, and during this interval will cause a a potential to be applied to brush 34 which has a value somewhere. between the values of the potentials applied to the two adjacent segments '33. This reduces the abruptness of change in control potential which would otherwise occur.

. Referring to Figure 2, it is assumed that it is desired to produce a filamentary winding whose pitch varies according to 'a predetermined pattern, for example a resistor having. aresistance curve of the exact shape represented by the heavy curve S which is the graph of some mathematical .function determined by the circuit conditions in which the resistor is to be used. Because the commutator 32 consists of a finite number of segments,

it will not be possible to attain ideal exactitude in producing the desired curve. Any desired degree of practical accuracy, may be acheived, however, by providing a sufiicient number of segments 33 in commutator 32 so that the pitch of the winding, although constant through- V out a distance corresponding to the length of a single commutator segment, will change a suflicient number of times throughout the entire length of the winding to produce, the required closeness of approximation. 7 V

A In the graph shown in Figurel, it is assumed that the three straight lines joining the points 0A, AB and BC will suflice as a working approximation of the curve S Obviously, a greater number of straight lines will result in a closer approximation. In the particular example illustrated,

' the'first three commutator segments 33 are supplied with difierentpotentials from source 37 which will produce the three winding pitches represented by the lines OA, AB and BC. It may become necessary at point C to change the size or the electrical conductivity of the resistancewire or both, in order to continue to point B on'curve S. In that case, it is assumed that two further lines. CA and A'B, for example represent the correct pitchwithin the desired degree of accuracy. The next two commutator segments will 'then be supplied with control potentials appropriate to the winding pitches represented by lines CA" and AB. In thisparticular example, five commutator segments and two wire .sizes produce the desired resistance curve with the required degree of accuracy.

If an alternating current control potential should be used, as described above, in conjunction with a variable ratio transformer or a variable reactor, there need be no finite number of points at which the winding pitch is changed. If a cam is used to'control the winding pitch, its surface may be made smooth throughout the active portion thereof, thus providing a winding in which the pitch varies gradually throughout its length without any abrupt changes in pitch, even though these might be very small. In the case of a variable ratio transformer,

or a variable inductive reactor, a core of smoothly vary- 7 to cover by Letters Patent is set forth in the appended claims.

I claim:

1. A winding machine for winding filamentary material on a support to produce windings of'non-uniform pitch, wherein the pitch is varied in accordance with a predetermined function of pitch versus length of winding on the support, comprising first drive means disposed to cause rotation of the support, material guide means operatively connected with a brush means and movable axially with respect to the winding, second'drive means disposed to cause said axial movement of the guide means, speed control means disposed to control the speeds of the first and second driving means with respect to each other, said speed control means being responsive to a control potential, a commutator having a plurality of individual segments, a source of potential including means for individually supplying each segment with a separate potential, said brush means being disposed for selective engagement with the commutator segments and caused to move with the motion corresponding to the motion of the wire guiding means to which it is operatively connected, and circuit means for applying the potential selected by said brush means to the speed control means.

2. A winding machine for winding filamentary material.

on a support to produce windings of anon-uniform pitch wherein the pitch is varied in accordance with a predetermined function of pitch versus length of winding on the support, comprising first drive means disposed to cause rotation of the support, 'rnaterial guide means mov-. able axially with respect to the winding and provided. with brush means connected thereto, second drive means disposed to cause said axial movement of the guide means, speed control means disposed to control the speed of said second drive means, said speed control means being responsive to a control potential, a commutator having a plurality of individual segments, a source of potential including means for, individually supplying each segment with a separate potential, said brush means being dis:

posed for selective engagement with thecommutator se'g v ments and caused to move bythe motion of the wire guiding means to which it is connected, and circuit means for applying the potential selected by said brush means provided with filamentary feeding means and brush means, the axial movement of said guide means causing a corresponding movement of said filamentary feeding means and said brush means, a commutator having-a plurality of individual segments each supplied with a source of separate potential, said brush means selectively References Cited in the file of this patent UNITED STATES PATENTS 5 Nicholson Jan. 25, 1910 Ewald Aug. 8, 1933 Tiselins Sept. 10, 1940 Cook Feb. 29, 1944 10 Gilman et al. Apr. 5, 1949 Van Alen Apr. 26, 1949 6 Path June 28, 1949 Baker et al Feb. 21, 1950 De Lange et a1. Mar. 14, 1950 Scott Sept. 18, 1951 Hale May 26, 1953 Harris, Jr. June 23, 1953 Van Alen Feb. 9, 1954 FOREIGN PATENTS Australia Dec. 24, 1945 Great Britain Aug. 13, 1948 

